1. Field of the Invention
The present invention relates to a valve assembly which is attached to a fuel gas storing cylinder or the like of an engine using compressed natural gas or liquefied petroleum gas as a fuel.
2. Explanation of Related Art
Japanese Patent No. 2,945,984 discloses a conventional example of the valve assembly which is employed for a fuel supply device of an engine using liquefied petroleum gas (LPG) or compressed natural gas (CNG) as a fuel. This conventional example comprises a cylinder valve attached to a gas cylinder. The cylinder valve and an engine are connected to each other through a fuel supply passage. The fuel supply passage has a mid portion provided with an electromagnetically opening and closing valve. The cylinder valve is manually opened and closed. The electromagnetically opening and closing valve is interlockingly connected to a key switch of the engine for opening and closing.
The conventional technique connects the cylinder valve to the electromagnetically opening and closing valve through a pipe line of the fuel supply passage. This entails a problem that it should be still improved on the following points.
The valve assembly must be connected to the pipe line at many portions and therefore the piping work is too troublesome to be effected inexpensively. Besides, it increases portions to be inspected as regards the airtightness, gas conductivity and the like with the result of making the maintenance work troublesome.
Although it can be considered to incorporate the electromagnetically opening and closing valve into a housing of the cylinder valve, a long non-use requires to manually close it with assuredness. When the cylinder valve comprising a manually opening and closing valve and the electromagnetically opening and closing valve are incorporated into one housing, the structure becomes so complicated that it cannot be put into practice at a low cost. In addition, as for the valve assembly used for the engine fuel supply device of this type, a high reliability is required. However, it is not easy to maintain at a high level of quality both of the manually opening and closing valve and the electromagnetically opening and closing valve incorporated into one housing. Further, in the case where the electromagnetically opening and closing valve has a defect, there is a problem that the maintenance costs high since the whole valve assembly must be replaced or the like.
The present invention aims at making it possible to effect an inexpensive piping, to enhance the reliability and to perform the maintenance easily.
In order to accomplish the above aim, the present invention has constructed a valve assembly in the following manner, for example, as shown in FIGS. 1 to 13.
A housing 16 comprises a first housing 17 and a second housing 18. The first housing 17 is fixed to a gas cylinder 1. The first housing 17 is formed with a gas inlet 20 to be communicated with an interior space 19 of the gas cylinder 1, a gas inlet passage 23, a first opening and closing valve 3, a first communication passage 24, and a communication outlet 25. The first opening and closing valve 3 is provided with a first valve seat 45 and a first valve chamber 44, into which a first closure member 46 is inserted. An actuation means 42 is interlockingly connected to the first closure member 46 through a transmission member 47. The actuation means 42 is manually operated so as to actuate the first closure member 46 for opening and closing with respect to the first valve seat 45.
On the other hand, the second housing 18 is formed with a communication inlet 29, a second communication passage 30, a second opening and closing valve 4, a gas outlet passage 31 and a gas outlet 32. The second opening and closing valve 4 is provided with a second valve seat 64, a valve closing spring 68, an electromagnetic device 43 and a second chamber 63, into which a second closure member 66 is inserted. The second closure member 66 is pushed to the second valve set 64 by a resilient force of the valve closing spring 68 and is moved in a valve-opening direction by energizing the electromagnetic device 43.
The second housing 18 is removably fixed to the first housing 17 through a fixing means 39. When the former is fixed to the latter, the communication inlet 29 communicates with the communication outlet 25.
The present invention functions as follows.
The first opening and closing valve 3 as well as the second opening and closing valve 4 is subjected to an inspection for its performance and quality independently before the second housing is assembled to the first housing 18. Then both of the housing 17 and 18 respectively provided with the opening and closing valves 3 and 4, each of which has a reliability high enough to have passed the inspection, are assembled to each other through the fixing means 39 into a valve assembly 2. In a state where the second housing 18 is fixed to the first housing 17, the first housing 17 has the communication outlet 25 mutually communicated with the communication inlet 29 of the second housing 18. Therefore, for example, as shown in FIG. 2, a fuel supply passage 5 to an engine 8 can have its piping completed only if it is connected to the gas outlet 32 of the second housing 18.
In the event that the second opening and closing valve 4 of the electromagnetically opening and closing valve undergoes maintenance or is replaced, the fixing means 39 is cancelled from fixing operation while closing the first opening and closing valve 3 of the first housing 17 fixed to the gas cylinder 1 to thereby remove the second housing 18 from the first housing 17.
The present invention offers the following advantages since it is constructed and functions as mentioned above:
(1) it is sufficient if the fuel supply device to the engine is connected to the gas outlet of the second housing. This reduces the portions to be connected for piping with the result of being able to effect the piping simply and inexpensively, to facilitate the inspection work for the gas leakage and the like and besides to enhance the reliability of the piping;
(2) The first opening and closing valve as well as the second opening and closing valve can be readily subjected to an inspection for its performance and quality independently before the second housing is assembled to the first housing. This can enhance the quality and reliability of whole the valve assembly; and
(3) The second housing can be readily removed from the first housing only by closing the first opening and closing valve with the first housing fixed to the gas cylinder and cancelling the fixing operation of the fixing means. This makes it possible to easily repair and replace the second opening and closing valve provided in the second housing when the second opening and closing valve of the electromagnetically opening and closing valve experiences a misoperation or disorder, which results in an easy maintenance of the valve assembly.
The present invention includes the following valve assembly.
As for the fixing means 39, concretely speaking, a tightening bolt can be employed. However, the fixing means 39 is sufficient if it can removably fix the second housing 18 to the first housing 17 and therefore may employ other fixing means.
The second housing 18 can be brought into direct contact with the first housing 17 for fixing, for example, as shown in FIG. 5, 8, 10 or 12. This case is more preferable because whole the valve assembly can be formed compact and there are fewer portions which need to be connected between mutual gas flow passages within the housing. Further, the second housing 18, for example, as shown in FIG. 13, may be fixed to the first housing 17 through a spacer block 78 or the like. In this case, the spacer block 78 and the like has an interior area formed with a gas passage 79, through which the communication outlet 25 communicates with the communication inlet 29 mutually.
Generally, the electromagnetic device 43 produces heat when energized. Then the first housing 17 is provided with a safety valve 27. This safety valve 27 is formed with a discharge hole 50 which is closed by a fusible alloy 51. In this case, in order for the fusible alloy 51 to hardly suffer from an adverse effect caused by the energizing, for example, as shown in FIG. 10 or FIG. 12, the second housing 18 is preferably fixed to the first housing 17 with the electromagnetic device 43 arranged remote from the safety valve 27.
For instance, as shown in FIG. 2, 6, 11 or 13, it is possible to arrange a bypass passage 33 which communicates the second communication passage 30 with the gas outlet 32, in parallel with the second opening and closing valve 4 and to provide in the bypass passage 33 a third opening and closing valve 34 which is manually opened and closed. In this case, the airtightness test or the gas conductivity test can be easily carried on the piping by opening the third opening and closing valve 34 without energizing the electromagnetic device 43 and therefore with the second opening and closing valve 4 closed.
For example, as shown in FIG. 2, 6, 11 or 13, the housing 16 is provided with a gas charging port 10. Arranged in parallel with the second opening and closing valve 4 is a gas charging passage 35 which communicates the gas charging port 10 with the interior space 19 of the gas cylinder 1. A check valve 11 is disposed in the gas charging passage 35 so as to inhibit the gas flow from the interior space 19 to the gas charging port 10. In this case, gas can be readily charged into the gas cylinder 1 without opening the second opening and closing valve 4 but by connecting a gas charging device to the gas charging port 10 directly or through a gas charging pipe 13.
Further, as shown in FIG. 11, the gas charging port 10 may also serve as the gas outlet 32. In this case, the gas charging passage 35 branches from a mid portion of the gas outlet passage 31. According to this structure, only one pipe play roles of the fuel supply passage 5 to the engine 8 and the gas charging pipe 13 with the result of simplifying the piping structure.
In the event that the housing 16 is provided with the gas charging port 10, a first filter 21 is arranged between the gas inlet 20 and the second opening and closing valve 4. The second valve chamber 63 communicates with the interior space 19 of the gas cylinder 1 through the first filter 21. Disposed between the gas charging port 10 and the check valve 11 is a second filter 36, through which the gas charging port 10 can communicate with the interior space 19 of the cylinder 1. According to this construction, the first filter 21 can get rid of dust and the like foreign matters produced within the gas cylinder 1 and the second filter 36 removes the foreign matters contained in the charged gas. This can prevent the clogging of orifices and so on in the valve assembly 2 and the attaching of foreign matters to the valve seats and the like with the result of maintaining the reliability on the valve assembly high over a prolonged period of time.
For instance, as shown in FIGS. 6 to 8, the housing 16 is provided with a gas cylinder connection port 73. And it is possible to arrange in parallel with the second opening and closing valve 4 a gas branching passage 74 which communicates the gas cylinder connection port 73 with an inter-space between the first valve seat 45 and the second valve seat 64. According to this construction, for example, as shown in FIG. 6, a gas outlet 83 of a valve assembly 82 attached to another gas cylinder 81 communicates with the gas cylinder connection port 73 through a gas communication pipe 75, thereby connecting a plurality of gas cylinders to one another. Gas within the another gas cylinder 81 is taken out of the gas outlet 32 through the gas cylinder connection port 73, the gas branching passage 74, and the second opening and closing valve 4.
At this time, as mentioned above, in the event that the housing 16 is provided with the gas charging port 10 and the gas charging passage 35, gas is charged from the gas charging passage 35 into the another gas cylinder 81 through the gas branching passage 74, the gas cylinder connection port 73 and the gas communication pipe 75. Thus a plurality of gas cylinders can be easily connected to one another without using any piping structure which has many portions to be connected, like a branched pipe or a cheese joint. Besides, since the gas within the another gas cylinder 81 is taken out of the gas outlet 32 via the second opening and closing valve 4, any electromagnetically opening and closing valve need not be provided in the valve assembly 82 of the another gas cylinder 81. Additionally, when gas is charged into the another gas cylinder 81, the above-mentioned connecting structure can be used to result in an easy arrangement of the gas charging pipe 13.
Moreover, for example, as shown in FIGS. 11 and 12, it is possible to provide the gas cylinder connection port 73 in the first housing 17 and to arrange in parallel with the second opening and closing valve 4, the gas branching passage 74 which communicates the gas cylinder connection port 73 with the first valve chamber 44.